[hobbit] Redundant Hobbit Servers

[Henrik Stoerner]

On Tue, Jun 21, 2005 at 11:13:01AM -0500, Lowery, Michael wrote:
> 
> Is there a better way than what I'm doing?  My goal is to have both
> servers configured the same, as much as possible, and have only one of
> them at a time send me alerts.  

The simplest solution is an active/passive cluster using a bit of 
shared storage (SAN, NAS or whatever). Put the Hobbit configuration-
and data-files on the SAN, and setup two hosts in an active/passive
cluster. When one host dies, make the cluster fail-over and start up 
Hobbit on the other.

There's a description of setting up a Linux cluster like this in the
"contrib/" directory in Hobbit 4.0.3+.

If you dont worry about preserving full history and trend graphs
in a fail-over situation, you can skip the shared storage requirement
and just setup the two hosts as a cluster. I'd then recommend using
rsync regularly to synchronize the configuration files and also the
checkpoint-files in the server/tmp/ directory - the checkpoint files
contain a snapshot of the Hobbit server memory so if those are copied
over to the failover server, it will start up with a fairly recent view 
of your system, including all of the info about what hosts have been
disabled, which alerts have been acknowledged etc. Synchronizing these
every 10-15 minutes will get you very close to a completely transparent
failover.


Regards,
Henrik